Consolidated Statements of Changes in Shareholders' Equity $ in Thousands	USD ($)
Total shareholders’ equity at beginning of period at Dec. 31, 2013	$ 2,514,161
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	127,892
Other comprehensive income (loss)	20,034
Stock option exercises (171,474 shares in 2015 and 384,775 shares in 2014)	20,109
Stock compensation expense recognized in earnings	4,696
Tax benefits related to stock compensation	1,664
Common stock issued in acquisition of WNB Bancshares (2,000,000 shares in 2014)	149,720
Purchase of treasury stock (140,571 shares in 2015)	0
Cash dividends – preferred stock (approximately $0.67 per share in both 2015 and in 2014)	(4,031)
Cash dividends – common stock ($1.04 per share in 2015 and $1.01 per share in 2014)	(62,660)
Total shareholders’ equity at end of period at Jun. 30, 2014	2,771,585
Total shareholders’ equity at beginning of period at Dec. 31, 2014	2,851,403
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	145,240
Other comprehensive income (loss)	(59,517)
Stock option exercises (171,474 shares in 2015 and 384,775 shares in 2014)	8,950
Stock compensation expense recognized in earnings	5,337
Tax benefits related to stock compensation	750
Common stock issued in acquisition of WNB Bancshares (2,000,000 shares in 2014)	0
Purchase of treasury stock (140,571 shares in 2015)	(10,594)
Cash dividends – preferred stock (approximately $0.67 per share in both 2015 and in 2014)	(4,031)
Cash dividends – common stock ($1.04 per share in 2015 and $1.01 per share in 2014)	(65,871)
Total shareholders’ equity at end of period at Jun. 30, 2015	$ 2,871,667